1. Field of the Invention
The present invention relates to a multipolar connector assembly utilized in a pacing lead.
2. Description of the Prior Art
Multiple electrode cardiac pacing leads are well known and have been utilized for pacing both the atrial and ventricular chambers of the heart.
Cardiac stimulation requires a reliable means for connecting electrical signals from a pulse generator, or pacer, to a pre-selected region on the wall of the heart. For example, a certain type of cardiac pacing lead is connected to a pacer, extends into the heart, and is placed in contact with the inside wall of the right ventricle. This lead normally takes the form of a long, generally straight, flexible, insulated conductor having one end electrically connected to the pacer and the other end connected to an electrode. The electrode is placed in contact with the wall of the heart.
On the other hand, pacing leads which are used for stimulation of the atrium are generally formed in a J-shaped configuration so that when the lead is inserted through a blood vessel and into the heart, the lead may be positioned to curve up into the atrial cavity.
Heretofore, pacing leads have been utilized which include a multipolar electrode assembly at the distal end thereof and a connector at the proximal end thereof for connecting the lead to a pulse generator. An example of such a lead is disclosed in U.S. Pat. No. 4,236,525 which discloses a lead assembly for a body implantable tissue stimulator having two distal electrodes and proximal connectors that are coaxially and axially spaced for mating with corresponding stimulator output electrodes in a pulse generator.
The connectors heretofore utilized for connecting the proximal end of a multiconductor conductor pacing lead to a pulse generator such as the connectors disclosed in U.S. Pat. No. 4,236,525 have worked satisfactorily. However, due to recent devleopments in cardiac pacing technology, leads having multiple conductors but of the same diameter or a smaller diameter than unipolar and bipolar leads are necessary.
The present invention takes the form of a novel connector at the proximal end of the pacing lead which includes one or more spool-shaped metal bands about the proximal end of the pacing lead and connected to individual wire conductors of the lead with an elastic conductive ring positioned about the spool. The elastic conductive ring is adapted to contact a metal sleeve embedded in the side wall of a socket in a body portion of the pulse generator into which the connector is inserted.
Also as will be described in greater detail hereinafter, the multipolar electrode assembly at the distal end of the multiconductor pacing lead is constructed in such a way as to facilitate solid electrical contact between the ends of each wire conductor in the multiconductor lead and individual electrodes of the electrode assembly and in such a way as to take up a minimum of space thereby to enable a very compact minimum diameter electrode.